FI88417C - Method and apparatus for cutting a tip drawing tape of a paper web - Google Patents

Description

B8417

Method and apparatus for cutting a paper web headband For use in a special purpose of a paper web 5

The invention relates to a method for cutting a paper web headband from a paper web and in connection therewith in a paper machine or similar multi-cylinder dryer and for applying said headband. by oblique drawing, in which method a water jet cutting device is arranged close to the paper web, from the nozzle of which a sharp water jet is applied to the paper web 10 and which device is traversed along the width of the paper web to apply the headband at full width.

The invention further relates to a water jet cutting device for cutting and spreading a paper web headband at an oblique pull, comprising a traversing bar extending over the entire IS width of the web and a movable carriage attached to its guide portions. a sharp jet or jets of water into the web.

A variety of bevel pulling devices are already known which are arranged on the drying section of a paper machine, in particular on the end of the drying section. In the prior art devices, a spike attached to a mechanical traverse is used as a cutting part of the paper web headband, which acts against the drying cylinder and with which oblique drawing, i.e. cutting into a full-width web, is performed. The disadvantage of this device is that the spike 25 scratches the cylinder and becomes dull quickly, thus deteriorating the cut. It is also known to use a circular cutting element similar to a circular saw blade placed in the traversing carriage of an oblique traction device.

The use of the mechanical cutting blades described above has had the disadvantage of e.g. the fact that the tension of the web varies in the transverse direction and there is flutter in the web, i.e. instability of its passage. As the web tension varies and the icicle blade causes a small bend in the web travel, relatively large changes in web travel are created with respect to the cutting blade 2,38417. Thus, in loan cutting devices adapted to the free runs of the paper web, the contact of the cutting blade with the passing web is not always made perfect.

In order to avoid the above-mentioned drawbacks, the applicant's FI patent 63 800 discloses a method and apparatus for fitting to said blade device a bearing surface substantially parallel to the plane of the passing web and blowing an air flow in said bearing surface to stabilize the web flow during cutting of said cutting blade.

10

In addition, such cutting devices are already known in which the cutting is performed with a sharp jet of pressurized water. Water jet cutting has several inherent advantages, which is why its use in paper web cutting and bevel drawing has become more common. It is therefore a main object of the present invention to further develop previously known water jet-based web cutting and bevel drawing methods and apparatus.

Prior art water cutting devices generally use a pressure booster attached to a cutting carriage. In this case, both the pressurized oil, the drain oil and the cutting water have to be brought to the cutting carriage by means of hoses supported by means of an energy transmission chain. Another known method is to place a pressure booster on the side of the machine and to direct high-pressure (150-1500 bar) water through a shielded hose to the cutting carriage, whereby the long hose causes considerable pressure losses and makes the structure complex, prone to malfunctions and difficult to maintain.

It is an object of the present invention to further develop previously known water cutting devices for paper web headband so that the disadvantages encountered therein can be largely eliminated.

In order to achieve the above and later objects, the method of the invention 30 is mainly characterized in that the system integrally connected to the water jet cutting device is charged with the necessary cutting water and the pressure energy required to produce its jet when the water jet cutting device is on the side of the paper machine.

The device according to the invention, in turn, is mainly characterized in that a pressure accumulator is arranged in connection with said carriage S, in which at least the entire pressure energy required for one oblique web can be stored, and that valve devices and connectors are connected to said pressure accumulator. to a pressure source for charging.

10 The present invention provides a number of advantages of various kinds at the same time, the most important of which are listed below:

Cross-machine pressure hoses and energy transfer chains with a large bending radius are not required.

IS - The equipment can be serviced and mounted on the side of the machine while the paper machine is running.

The cutting beam can be lowered and narrowed because there is no need to hide the pressure hoses inside it.

Thanks to its simple design, the device is reliable.

The mass of the cutting carriage is reduced and the hoses slowing down the operation can be omitted, whereby the speed of movement of the carriage can be increased and the force required to stop it can be reduced.

Interruption sensitivity is reduced due to the simplified structure.

Oblique traction can be performed in an even smaller space.

Occupational safety is improved, especially due to the elimination of pressure hoses.

25 - Cleaning and other maintenance are made easier by the simplicity of the device's construction.

In the following, the invention will be described in detail with reference to some application examples of the invention shown in the figures of the accompanying drawing, to the details of which the invention is in no way narrowly limited.

4,38417

Figure 1 shows a hydraulic diagram of a device according to the invention.

Figure 2 shows an axonometric view of the main principle of the oblique drawing.

Figure 3 shows a side view of a device according to the invention.

Fig. 4 shows a pressure accumulator used in the invention as seen from the direction A indicated in Fig. 3.

Figure 5 shows various alternative positions of the oblique traction device according to the invention, the so-called in an inverted cylinder group.

Figure 6 shows different placement positions of the oblique traction device according to the invention, the so-called in a normal cylinder group.

15

The principle of cutting and skewing of the web W is shown schematically in Figure 2. The web W passes over the heated drying cylinders 20 of the paper machine. After a break in the web W, the end of the web must be passed over the cylinders 20. For this purpose, a headband R is cut from the other edge of the web W, which is passed through the drying section under the guidance of air blows and / or head ropes. The headband is cut with a water jet S from the nozzle 15 and the machine direction cut is marked C in Fig. 2. The web portion Wp remaining outside the headband R is directed to the pulper or scrap conveyor below. Once the passage of the headband R has been stabilized from a suitable section, a headband R of about 10-15 cm width is applied with a water jet cutting device according to the invention, the so-called with a bevel drawn schematically in Fig. 2 by the broken line Cv.

The method and device according to the invention differ substantially from the previously known methods and devices for cutting and skewing paper web W in that a pressure accumulator 11 is arranged in the cutting carriage 24 shown in Fig. 3 and connected to a cutting nozzle 5,88417 by means of a valve and possibly a pressure booster 12 15. The pressure accumulator 11 is charged on the side of the paper machine, preferably on its treatment side, by means of a pressurized water unit, whereby the amount of water and the amount of pressure energy required for at least one cross-section of the web W are supplied to the pressure accumulator 11. According to Figure 1, the pressurized water unit comprises a high-pressure pump 13 and a quick connector 14.

5

The water required for surgery is stored either in the pressure accumulator 11 itself, which has a gas space separated by the membrane, or in a separate water tank to which the gas-filled pressure accumulator 11 is connected. As the pressure accumulator, a membrane battery or a bladder battery known per se is used, which contains an overpressure gas, e.g. nitrogen. The total volume of the pressure accumulator 11 is e.g. 10 1 10 and it stores the amount of water required for one oblique traction, which is of the order of 1 ... 2 1. The charge pressure of the pressure accumulator 15 is usually in the range of 100-400 bar. In this case, a needle-like water jet with a volume flow of the order of 0.2 l / min is obtained from a nozzle 15 with a diameter of about 0.1 to 0.3 mm. Such a jet S is sufficient to cut even a thick web W, but it does not wet the edge strip R. With the above values 15, an amount of about 1 l of water is sufficient to perform one oblique pull, which can be charged to a pressure accumulator with a capacity of about 10 l at the above pressure.

In the following, the mechanical structure of the device according to the invention will be described mainly with reference to Figures 3 and 4.

20

The pressure accumulator 10 of the water cutting device is attached to the traversing carriage 24 by connectors 16. Said carriage has at least four wheels, namely a pair of lower wheels 26a and a pair of upper wheels 26b, the grooves of which rest on the guide edges 25a and 25b of the traverse beam 27. The traversing beam 27 extends over the entire width of the web W. The traversing beam 27 25 is attached to the support flanges 28 from both the operating and maintenance side of the machine, which are attached to the machine body parts 17 by horizontal articulated shafts 29. The traversing beam 27 can be pivoted to and from the operating position shown in Fig. 3 by means of hydraulic cylinders 18. The piston rods of the hydraulic cylinders 18 are attached to the support flanges 28 by shaft pins 18a.

30 6 38417

When the pressure accumulator 11 is on the side of the machine in the charging position, where the quick connector 14 is connected to the water connection of the high-pressure water pump 13, the traversing bar 27 is turned away from the cutting position shown in Fig. 3. According to a preferred embodiment of the invention, the charging of the pressure accumulator 11 is continued and during the longitudinal section C (Fig. 2) S of the edge strip R, the cutting bar is turned to the cutting position shown in Fig. 3 and a sharp water jet S from the nozzle 15 cuts the longitudinal section C into the web. throughout the longitudinal section C of the edge band R. The pressure energy charged to the pressure accumulator 11 is utilized only during the actual oblique drawing Cv, whereby the energy 10 charged to the pressure accumulator 11 is converted into a web-cutting water jet S. This reduces the energy storage requirement of the pressure accumulator 11 than in an embodiment of the present invention. with the energy stored in the pressure accumulator 11 so that the quick connector 14 is open during section C.

15

A motor and a wire or chain drive located outside the traverse beam 27 are preferably used to traverse the cutting carriage 24. A toothed rail or a long actuating cylinder blade is also possible in providing a traverse movement. Traversing mechanisms are not per se within the scope of this invention, so they are not described in more detail in this context.

Figures 5 and 6 show some alternative locations for the water jet cutting device 10 according to the invention. It should be emphasized that, in general, only one of the cutting devices 10 shown in Figures 5 or 6 is required. Figure 5 shows the so-called an inverted cylinder-25 group in which the steam-heated drying cylinders 20 are in the top row and the reversing cylinders 20 in the bottom row. The web W passes, supported by the drying wire F, so that with the drying cylinders 20 the web W comes immediately heated against the surface of the cylinder 20. The water jet cutting device 10 according to the invention is placed either on the run of the drying wire F and the web W which runs from the drying cylinder 20 to the turning cylinder 21 30 or vice versa. Fig. 5 also shows, as an alternative, a solution in which the drying wire F is separated from the web W by a pair of guide rollers 22, 23, whereby the web W

7 S 8 41 7 a free tension W0 is obtained, with which the section C of the web headband R and the oblique tension Cv can advantageously be performed.

Figure 6 shows an application environment of the invention in which 20 denotes drying cylinders and 21 denotes either drying cylinders or reversing cylinders. The water jet cutting devices 10 are located either on the free tensions of the web W between the cylinders 20 and 21 or to act against the cylinder 20, which position is indicated by reference 10A.

In the following, the claims are set out, within the scope of the inventive idea defined by the invention, the various details of the invention may vary and differ from those set forth above by way of example only.

Claims (10)

A method in or in connection with the bulk cylinder dryer (20,21,22,23) of a paper machine or the equivalent for cutting a tip drawing band (R) from the paper web (W) and for spreading said tip drawing band (R) by means of so-called. oblique drawing (Cv), in which method a cutting device (10) operating with a water jet is contacted with the paper web (W), from whose nozzle (13) a pointed water jet (S) is directed towards the paper web (W). ) and wherein the device is traversed in connection with the tip drawing across the width of the paper web 10 (W) to extend the tip drawing tape (R) to its full width, characterized in that the system stationary to the cutting device (10) which operates with a water jet recharges the amount of schematic water needed in the oblique draw and the pressure energy needed to achieve its jet while the water jet schematic device (10) is in a position where it is traversed on the IS side of the paper machine. 2. A method according to claim 1, characterized in that in the method the machine-directed cutting (C) is performed by the tip drawing band (R) while the water jet cutting device (10) is connected to its pressurized water source (13) and the skew (Cv) is performed. by means of surface energy charged in the stationary pressure accumulator (11) while the device (10) is detached from its source of water (13). 3. A method according to claim 1 or 2, characterized in that the water needed for cutting the web (W) is stored either in pressure accumulators (11) or in a separate water container connected thereto and the pressure accumulator (11) and the possibly the water tank is connected to a pressure booster (12) and to a water source (13) while the oblique (Cv) bends with the aid of a quick-release joint (14) which. opens automatically. 30 12 3 8 41 7 Method according to any one of claims 1-3, characterized in that the quick-release joint (13) between the pressure accumulator (11) and its water source (13) is arranged to be fixed automatically after the performance of the cutting and return movement for a new charge of the pressure accumulator (11). 5 Process according to any of claims 1-4, characterized in that the charge pressure on the gas in the pressure accumulator (11) is set in the range of about 100-400 bar and / or that in the pressure accumulator (11) or in a separate water container connected to this, water is charged for at least one obliquity most preferably about 1 ... 2 1 10 and / or by feeding the sputtering nozzle a water jet whose volume flow is of the class 0.2 l / min. Method according to any one of claims 1-5, characterized in that the machine-directed cutting (C) of the tip drawing belt (R) and the skewing (Cy) is carried out in the free space (Wq) of the paper web, against the drying cylinder (20) or the breaking cylinder. (21) or roller and / or against the drying wire (F) (Figures 5 and 6). A water jet cutting device intended for cutting a tip drawing band (R) of a paper web (W) and for propagating it by means of oblique, the device comprising a traverse beam (27) extending over the entire width of the web and a movable web. sledge (24) fixed in conjunction with its guide members (25,25a, 25b), which slidable can be traversed across the entire width of the paper web (W) to be cut and to which sledge (24) attaches a water jet nozzle (15) or corresponding arrangement 25 of nozzles with which an acute water jet (S) or jets is directed towards the web (W) to be cut, characterized in that a pressure accumulator (11) is arranged in connection with said sledge (24), in which can store all of the pressure energy needed for a tip drawing (Cv) of the web (W), and that valve means (12) and connections (14) are connected to said pressure accumulator, with which a pressure accumulator (11) can be connected to pressure Llan (13) for charging when the device (10) is on the side of the paper machine. '3 58417 Apparatus according to claim 7, characterized in that said pressure accumulator (11) or the water container connected thereto is arranged in such a way that the amount of schematic water needed for at least one oblique can be charged therein, which is most conveniently of class 1. ..2 1. 5 9. Apparatus according to claim 7 or 8, characterized in that the device includes a quick-release joint (14) that fits with its pressure source (13), which joint is arranged in such a way that the machine-directed cutting (C) of the tip drawing belt (R) can be performed while said quick-release joint (14) is coupled such that the shear energy 10 is supplied from the pressure source (13), and that said quick-release joint (14) is arranged to open automatically when the skew (Cy) bends. 10. A device according to claim 9, characterized in that said quick-release joint (14) is arranged to be closed after the return movement of the oblique to connect the pressure accumulator (11) of the device (10) to the pressure source (13) for a new charge.